Brisbane tree guide

Grey box tree

Eucalyptus moluccana · also called Gum-topped box, Coastal grey box

The grey box tree, often called gum-topped box in Queensland, is a native eucalypt whose trunk is clad in rough grey bark while the upper branches are smooth and white. It grows naturally in South East Queensland woodlands, often on heavier soils, and Brisbane City Council lists it among the trees koalas eat. Its timber is very hard, durable and termite resistant. At 20 to 30 metres tall it suits acreage and parks, not small yards.

Native to South East Queensland
20 to 30 m tall
Flowers October to February

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Grey box, from Wikimedia Commons — Photo: Mark Marathon, CC BY-SA 3.0, via Wikimedia Commons

Grey box at a glance

Height: 20 to 30 m
Spread: 10 to 15 m
Leaves: Evergreen
Flowers: White, October to February
Roots: Aggressive
Origin: Eastern Australia, from Nowra (NSW) north to the Atherton Tableland (Qld)
Family: Myrtaceae

How to identify a grey box

The trunk carries thin, rough, finely chequered grey bark, sometimes mottled grey and white, which gives way to smooth white, cream or pale grey bark on the upper branches, often shed in ribbons. Adult leaves are glossy green, lance-shaped and 7 to 17 cm long, and the same colour on both sides; seedlings and regrowth have broad, egg-shaped leaves. Buds come in groups of about seven, are diamond to spindle shaped and open to white flowers. The gumnuts are small, cup to barrel shaped and 4 to 7 mm long. A rough box-barked trunk under smooth white branches and a glossy green crown is the main clue.

Growing a grey box in Brisbane

Grey box is a local. The Queensland Herbarium describes South East Queensland woodlands dominated by it on the edges of alluvial plains, and it also grows in mixed eucalypt forest on hills and ranges. It prefers heavy alluvial valley soils, but also grows on basalt and limestone slopes, and it is hardy in drier spots. Koalas feed on it across the region. As a 20 to 30 metre tree with a wide canopy, it suits acreage, parks and koala habitat plantings rather than suburban blocks.

What to watch out for

Size is the main issue. Grey box reaches 20 to 30 metres with a canopy 10 to 15 metres wide, and Unitywater lists large gum trees among those not to plant near water and sewer pipes. Keep it well away from the house, pipes and power lines. Koalas feed on it in South East Queensland, so check for wildlife before any pruning or removal.

Size. It grows into a medium to tall tree of 20 to 30 metres with a canopy 10 to 15 metres wide, too big for most suburban yards.

Pruning and care

Grey box needs little routine care. Water young trees until they are established, then leave them be, as the species is hardy. Prune only to remove dead, damaged or crossing branches or to keep clearance over roofs and driveways, cutting just outside the branch collar. The tree can reshoot from a woody swelling at its base, called a lignotuber, and from buds under the bark after fire. Because of its height, any work above ground level is a job for a qualified arborist.

Grey box: your questions

Short answers, from the sources below.

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Do koalas eat grey box?

Yes. Brisbane City Council lists gum-topped box, as grey box is often called in Queensland, among the eucalypts koalas eat in South East Queensland, and Land for Wildlife lists it as a regional koala food tree.

How tall does a grey box tree grow?

Business Queensland describes it as a medium-sized tree of 20 to 30 metres with a trunk up to 1 metre across, and the canopy can spread 10 to 15 metres.

Is grey box the same as gum-topped box?

Yes. Both names refer to Eucalyptus moluccana. Brisbane City Council uses gum-topped box, while PlantNET in New South Wales uses grey box, and coastal grey box is another name.

Are grey box roots invasive?

Unitywater lists large gum trees among plants not to put near water and sewer pipes. Grey box isn't named individually, but at 20 to 30 metres it should be planted well clear of pipes and the house.

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Sources and credits

Photo: Mark Marathon, CC BY-SA 3.0, via Wikimedia Commons.

This profile updates sheet 47 of the plant profile booklet made for Colourful Tree Lopping in 2013. We checked every fact against current sources and rewrote it for the guide.

Checked October 2026. Weed listings and council rules change: check the council's and the Queensland Government's pages before you act.